1. The Field of the Art.
This invention relates to an apparatus for sterilizing a root canal and more specifically to a root canal sterilization apparatus that uses bactericidal ultra-violet rays to sterilize bacteria in the root canal.
2. Description of the Prior Art.
Bacteria in the root canal are important causal agents for apical periodontal inflammation. Therefore, for indodontal treatment, it is essential to remove bacteria from the root canal.
Previously, for removal of bacteria from the root canal, the following method has been used. Initially, the root canal is spread with a reamer or the like while being washed. Then, for the purpose of sterilizing the bacteria remaining in the root canal, a cotton plug impregnated with a sterilizing disinfectant, such as form cresol, is inserted into the root canal. Thereafter, washing of the root canal, and replacement of the cotton plug are carried out one or two more times. After this treatment, if no clinical symptom is detected and no abnormal clinical condition is observed inside the root canal, the final treatment of root canal filling is carried out.
However, the above-described method takes a relatively long time, one or two weeks, for sterilization, thus making the patient uncomfortable.
Furthermore, using this sterilization method, a high probability exists that after the root canal is filled, the inflammation will reoccur. This is because conventional chemical sterilization cannot completely sterilize the bacteria in the root canal and some bacteria still remain.
This difficulty may be eliminated by using a more effective germicide or by employing a method in which the root canal filling is carried out with a sterilizing disinfectant. However, these methods are undesirable because of the adverse effect of those chemicals when administered directly on the cells.
It is also well known that bactericidal ultraviolet rays (light 200 to 300 nm in wavelength) can sterilize bacteria. Use of the bacteriocidal ultraviolet rays is advantageous in that it will cause no danger of residual medicines.
However, the light source for generating such bacteriocidal ultraviolet rays is a bar-shaped lamp with an outside diameter of at least 10 mm and a length of 50 mm. With this size, it is impossible to insert it into the root canal spread (which has an inside diameter of about 1 to 1.5 mm). Also, a light source of this type usually incorporates mercury. Because of the toxicity of mercury, it is undesirable to insert it into the buccal cavity.
Therefore, bacteriocidal ultraviolet rays have not been used to sterilize bacteria in the root canal.